Multi WAN IP's - NAT SAME

Hi all, I have 2 questions.

  1. If I use “same” NAT with address range, will my customer always receive same NAT IP? or is it just per connection if source and destination are the same? I want my customers to always get same NAT IP for whatever connection they initiate..will “same” NAT achieve this? If not what will?

  2. I will receive a /24 subnet for public addresses, do I have to add each address to the WAN interface? Is there an easier way of doing this?

Thanks